The physiological role and effects of divalent ions on the ionic permeability, electrical properties, and energy metabolism of the lens will be studied. This will include the metabolism of endogenous divalent ions, especially, in this phase of the work, calcium, magnesium and zinc. The process of accumulation and the distribution of these molecules will be studied, including elucidation of the role of the lens capsule, anterior epithelium and fibers. Particular emphasis will be placed on the effects of drugs and toxic metal ions on such aspects of the ionic regulation of the lens.